TU-tagging: cell type-specific RNA isolation from intact complex tissues.
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ABSTRACT:
SUBMITTER: Miller MR
PROVIDER: S-EPMC2783170 | biostudies-literature | 2009 Jun
REPOSITORIES: biostudies-literature
Publications
TU-tagging: cell type-specific RNA isolation from intact complex tissues.
Miller Michael R MR Robinson Kristin J KJ Cleary Michael D MD Doe Chris Q CQ
Nature methods 20090510 6
We found that the combination of spatially restricted uracil phosphoribosyltransferase (UPRT) expression with 4-thiouracil delivery can be used to label and purify cell type-specific RNA from intact complex tissues in Drosophila melanogaster. This method is useful for isolating RNA from cell types that are difficult to isolate by dissection or dissociation methods and should work in many organisms, including mammals and other vertebrates. ...[more]
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Project description:We show that the combination of spatially restricted uracil phosphoribosyltransferase (UPRT) expression with 4-thiouracil (4TU) delivery can be used to label and purify cell type specific RNA from intact complex tissues. This method is useful for isolating RNA from cell types that are difficult to isolate by dissection or dissociation methods and should work in any organism where UPRT can be spatially expressed, including mammals and other vertebrates. To confirm that thio-labeled RNA was from UPRT-expressing cells and demonstrate the utility of TU-tagging for cell type-specific RNA isolation, we purified TU-tagged and untagged RNA and compared them using microarrays. We chose to isolate RNA from larval glia, which are present in low number, are highly dispersed, and have a complex cell morphology, making them one of the most difficult cell types to isolate by dissection or dissociation methods. We used reversed polarity (repo)-GAL4 to drive expression of UAS-UPRT specifically in glial cells of the larval brain. We purified TU-tagged and untagged RNA from 72-96h larval brains, and hybridized them to custom Agilent microarrays. We performed two biological replicate experiments.
2010-06-19 | E-GEOD-15445 | biostudies-arrayexpress
Project description:We show that the combination of spatially restricted uracil phosphoribosyltransferase (UPRT) expression with 4-thiouracil (4TU) delivery can be used to label and purify cell type specific RNA from intact complex tissues. This method is useful for isolating RNA from cell types that are difficult to isolate by dissection or dissociation methods and should work in any organism where UPRT can be spatially expressed, including mammals and other vertebrates.
2009-04-24 | GSE15445 | GEO
Project description:Transcriptional profiling is a powerful approach for understanding development and disease. Current cell type-specific RNA purification methods have limitations, including cell dissociation trauma or inability to identify all RNA species. Here, we describe "mouse thiouracil (TU) tagging," a genetic and chemical intersectional method for covalent labeling and purification of cell type-specific RNA in vivo. Cre-induced expression of uracil phosphoribosyltransferase (UPRT) provides spatial specificity; injection of 4-thiouracil (4TU) provides temporal specificity. Only UPRT(+) cells exposed to 4TU produce thio-RNA, which is then purified for RNA sequencing (RNA-seq). This method can purify transcripts from spatially complex and rare (<5%) cells, such as Tie2:Cre(+) brain endothelia/microglia (76% validated by expression pattern), or temporally dynamic transcripts, such as those acutely induced by lipopolysaccharide (LPS) injection. Moreover, generating chimeric mice via UPRT(+) bone marrow transplants identifies immune versus niche spleen RNA. TU tagging provides a novel method for identifying actively transcribed genes in specific cells at specific times within intact mice.
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Project description:Purification of cell type-specific RNAs remains a significant challenge. One solution involves biosynthetic tagging of target RNAs. RNA tagging via incorporation of 4-thiouracil (TU) in cells expressing transgenic uracil phosphoribosyltransferase (UPRT), a method known as TU-tagging, has been used in multiple systems but can have limited specificity due to endogenous pathways of TU incorporation. Here, we describe an alternative method that requires the activity of two enzymes: cytosine deaminase (CD) and UPRT. We found that the sequential activity of these enzymes converts 5-ethynylcytosine (EC) to 5-ethynyluridine monophosphate that is subsequently incorporated into nascent RNAs. The ethynyl group allows efficient detection and purification of tagged RNAs. We show that 'EC-tagging' occurs in tissue culture cells and Drosophila engineered to express CD and UPRT. Additional control can be achieved through a split-CD approach in which functional CD is reconstituted from independently expressed fragments. We demonstrate the sensitivity and specificity of EC-tagging by obtaining cell type-specific gene expression data from intact Drosophila larvae, including transcriptome measurements from a small population of central brain neurons. EC-tagging provides several advantages over existing techniques and should be broadly useful for investigating the role of differential RNA expression in cell identity, physiology and pathology.
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